Currently, in the coaxial access field, data is transmitted between a cable modem termination system (CMTS) and a cable modem (CM) through an uplink channel and a downlink channel.
In the coaxial access field, a mainly used standard is the data over cable service interface specification (DOCSIS) 3.1. Based on the DOCSIS 3.1, a full-duplex standard data over cable service interface specification (full duplex DOCSIS) is provided. According to the full duplex DOCSIS, a co-time co-frequency full duplex (CCFD) communication manner is used on a CMTS side, and a time division duplex (TDD) or frequency division duplex (FDD) communication manner is used on a CM side. In this case, particular bandwidth is allocated to the CM to serve as an uplink channel or a downlink channel. The CM needs to demodulate data received through the downlink channel before identifying and using the data, and the demodulation needs a channel parameter of the downlink channel.
According to the DOCSIS 3.1, in a conventional channel parameter estimation manner, a data frame sent by the CMTS to the CM through the downlink channel carries a discrete pilot signal, and the CM may estimate the channel parameter of the downlink channel based on the discrete pilot signal in the received data frame. However, the CM needs to receive at least one complete data frame, so that the CM can obtain sufficient discrete pilot signals from the data frame, to estimate the channel parameter of the downlink channel. Before estimating the channel parameter of the downlink channel, the CM cannot correctly demodulate data received through the downlink channel. It can be learned that according to the DOCSIS 3.1, a time for obtaining at least one data frame needs to be consumed from starting to estimate the channel parameter of the downlink channel by the CM to estimating the channel parameter by the CM. Consequently, the time required by the channel parameter estimation is relatively long, and time efficiency of bandwidth allocation is affected.